Minutes of the LIS Section meeting held on 17^th January 2011

Present: G. Arduini, H. Bartosik, S. Gilardoni, J. Gil Flores, A. Lachiaze, M. Newman

General Information (Gianluigi) 

• From IEFC on 10/12/2010:
  • At the last Research Board:
    • ELENA discussed. Strongly supported. Resources to be found.
    • 2011 schedule approved. Extension of CNGS and nToF granted.
• Biocell training will be compulsory for getting access in the SPS starting from middle of next year
• Fragmented ion tests for NA61 were successful. The new optics with reduced beat at the splitters as calculated by Olav was implemented before the low energy runs.
• From Evian:
  • Aim for 1 fb^-1 or more in 2011 (although 3 fb^-1 or more looks feasible)
  • Luminosity of 10³³cm^-2s^-1 is within reach
  • 150 ns spacing to start and to get back to 300-400 bunches
  • 75 ns then after scrubbing
  • We will run with emittances smaller than nominal, emittances of 2-2.5 mm could be regularly achieved with the 150 ns beam
  • Major concerns: UFOs and e-cloud
  • Energy to be discussed in Chamonix (24 to 28th January)

Simone said that it might be possible to increase the bunch intensity for the 150 and 75 ns above nominal intensity.

Problem with the 80 MHz cavity is understood. It was due to a mechanical problem with the tuner. A modification is going to be implemented to avoid that the problem re-appears.

One of the future MSWG meeting will be dedicated to discuss beam requirements. One possibility would be to run with the 50 ns beam with single batch injection in the PS (emittances will be larger) and then take the small emittance 75 ns beam obtained with double batch injection.

PS2 - single particle dynamics (Hannes) - slides

The focussing and defocussing quadrupoles are of the same type, the vacuum chamber only is different.

In the tune diagram plot red lines represent structural resoances while blue ones are not structural. Dashed lines represent resonances excited by skew elements.

Simone noted that octupoles are not included in the lattice. These could be necessary for Landau damping

108 BPMs are planned. This provides an extremely good phase coverage. Hannes mentioned that this has not been optimized.

The estimated aperture of the machine (3.5 sigmas) takes into account tolerances in orbit distortion and beta beating which are consistent with those seen after correction.

Error table for magnets taken form JPARC measurements. Degradation of the stable area when errors are included, largest impact is due to dipole errors (b5 and b7). The dynamic aperture is nevertheless larger than the physical aperture defined by the collimators.

MTE for PS2 (Antoine) - slides

The MTE study has been performed at 11.75, 6.71 but no magnetic errors have been included.

The ring is fully matched for change in tune.

Two octupoles and one sextupoles are used for the MTE capture. Including the correction of the non-linear coupling

Longitudinal motion has been considered

The presentation could not be completed due to the lack of time (another meeting starting in the same room) ==> postponed to the next meeting. Thanks Antpoine!

Next meeting

Monday, 14^th February 2011 at 14:00 in room 354-1-001

Agenda

• General information (Gianluigi)

• MTE for PS2 (Antoine)

• Round table (all)

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